8 out of 10 times my 1985 K100 RT will smoke on start even if I lean it to the right first and then park on the center stand. It smokes for 10 to 30 seconds and then stops. I had previously searched the forum for "smoke" and read all the articles. Since it still happened on the center stand and I drained the oil and put exactly 3.6 quarts back in,  I started to think it was an O-ring. But now due to the randomness i think it has to do more with the design flaw later fixed. Do you have to leave the bike running while leaning to the right, shut off and hold for a bit more?

Also, whenever I use the side stand after a ride when some time has passed I can check the oil sight glass and it is white.
However when I use the center stand it always seems to stay black. Is the proper reading from this gauge supposed to be white on top and black on the bottom, red dot indicating the high point of oil?

Thanks!

Ah. No one has explained the secret of the K.
Forget about leaning to the right. It will fall over sooner or later.
Early K100's did not have the piston rings pinned, they can rotate, line up the gaps and let oil past for a while.
Best way to deal with it is to let the bike tick over for about 10 seconds when you pull up. Look cool removing your gloves or sunglasses and then switch off.
After that, it doesn't matter if its on the side or centre stand, it should be fine when you start up again.
Now you're one of us.

The sight glass will almost always be empty or white on the side stand as the oil is to the low side of the engine.  Full on the centerstand is to the middle red dot.

85 has non-pinned rings which move around and can let oil into the combustion chamber.  Comberjohn's suggestion works as well as any.  THe smoke does work well for keeping mosquitoes at bey

Just to clear up a misconception regarding the oil sight glass, the red circle is for the oil level...top of the circle is the upper limit and the bottom of the circle is the lower mark.

The red dot has nothing to do with the level of the oil.

...unless Inge chimes in and corrects me!  

We always learnt bike on main stand and the red dot for the oil level.

4 stroke engines don't normally have the piston rings pinned. But the engines are usually vertical or near vertical. So the ring end gaps eventually line up and you get. . . Smoke. So later engines have the rings pinned like in a 2 stroke so the ends of the rings don't break at the transfer ports.

Exactly as posted!

But, how come the boxers don't smoke!!! I bet they are pinned.

blaKey wrote:Just to clear up a misconception regarding the oil sight glass, the red circle is for the oil level...top of the circle is the upper limit and the bottom of the circle is the lower mark.

   Just exactly, blaKey   .

That is a little book I don't have. But either way the red dot aimed for is fine. That's where I aim to keep it all the time.

Comberjohn wrote:Ah. No one has explained the secret of the K.
Forget about leaning to the right. It will fall over sooner or later.
Early K100's did not have the piston rings pinned, they can rotate, line up the gaps and let oil past for a while.
Best way to deal with it is to let the bike tick over for about 10 seconds when you pull up. Look cool removing your gloves or sunglasses and then switch off.
After that, it doesn't matter if its on the side or centre stand, it should be fine when you start up again.
Now you're one of us.

Thanks for the advice.
What I don't get is I'll start it up in the morning on the center stand. No Smoke. I'll give at few revs / let it idle for 30 seconds or so and then shut it off. I'll come back later in the day to go for a ride and it smokes. When you say "tick over" I assume you mean "idle"?

They all do it some more than others its no big deal and if anybody says anything about it just deny it and blame a honda

I somehow discovered that the bike doesn't always smoke.   

Seems like upon starting if the bike is allowed to idle for about a minute it doesn't smoke, or the smoke is greatly diminished. But, if I rev the engine right after starting I get a cloud of smoke.

(ComberJohn) Is your point: Allow the bike to idle while on the side stand(?), before switching-off. I don't understand: (Respectfully) Please explain how that makes a difference.

Just let it idle(tick over) while sitting on it. Not on either stand.
Like I said, just look cool lifting your visor and taking off your gloves before switching off. Then put it on any stand you like.
Someone (Rick?) suggested that it might be caused by a gearwheel at the rear of the engine chucking oil at the bottom of the rearmost piston and by allowing things to settle down, lets oil drain from the back cylinder.
Its only a theory but it works for me!

Maybe there is some truth in the theory about oil being thrown on to the bottom of the rear piston.
The boxer engine may not have the same issue.
However, weren't the later brick engines supplied with pinned rings?
Although, I have seen later bricks smoke a bit too.

Airhead boxers DO smoke if left on sidestand which is why you rarely see them used. Also they were
very awkward to deploy, think toe extended under the left cylinder way forward, stand slips off toe and self retracts! Rider has to catch the weight with leg in less than ideal location.

I didn't think the boxer rings were pinned. Its a normal requirement for 2 stroke engines because of the transfer ports and making sure the ring ends don't eventually end up in the port and snap. as for how much a ring will migrate around its groove, I don't have a clue. I don't imagine this got a lot of thought at the time because its only a matter affect use of the side stand. A lot of engines have oil either splashing or spraying on the underside of the pistons and the piston rings keep it in the crank case. If there was an engine problem it would be burning oil all the time. However because it only happens on start up not much oil is lost. The upside is probably less wear in the bores and engine because of the oil in the bores.

One thing that I consider has a bearing is that if the cylinder that collects the oil has both valves closed then it burns the oil on start up but if the valves are on overlap then the oil gets into the exhaust pipe and takes ages to burn out because the exhaust has to get hot before it burns.
One more thing is don't believe that the pins to prevent the rings turning is a fix as all 3 Ks I have owned and ridden had the pined rings and all 3 smoked worse than George Burns with a dozen cigars.  It is a help but by no means a fix.

I didn't mean to suggest pinning the rings would cure the smoking, it will only reduce it. I could also make my 92LT smoke as much as an early K........

My K stopped smoking on startup after I replaced a very clogged fuel filter, oddly enough.

Took an Advanced Rider Safety Course Yesterday. There was a total of 11 starts I did over a total of 10 hours. 2 in the morning and the other 9 in the afternoon when we were at the course. I was starting the bike every half hour in the afternoon. I was worried I was going to smoke out the group so I tried to stay towards the back after each exercise. At each stop I let the engine idle while I took off my gloves & sunglasses. Then I stopped the bike and kept it straight up while I took off my helmet, put the gloves and glasses in it, lowered the side stand and dismounted.

It only smoked 2 of the 11 times.

Other note. The 7L fuel warning light came on early. The tank was very hot. I pulled into gas station on way home and then pulled out because I could see I had only used up "1 inch" of gas. I was hoping the half hour ride on the highway would cool the bike and turn the light off but it didn't. Let the bike cool for an hour at home ( watched second half of USA vs Portugal) and it was off.

I just bought a K100RS '85 model with 170,000km on the clock from a guy who says he reduced the smoke on start up significantly when he changed out / renewed the valve stem seals. This is often a significant factor on higher mileage motorcar engines as we know so it's a possible contributory factor for those who suffer more than others (I guess?)

bignews1and2 wrote:Took an Advanced Rider Safety Course Yesterday. There was a total of 11 starts I did over a total of 10 hours. 2 in the morning and the other 9 in the afternoon when we were at the course. I was starting the bike every half hour in the afternoon. . . .

Other note. The 7L fuel warning light came on early. The tank was very hot. I pulled into gas station on way home and then pulled out because I could see I had only used up "1 inch" of gas. I was hoping the half hour ride on the highway would cool the bike and turn the light off but it didn't. . . .

Typical heat problem on K100. I have the same model year.

Problem is, once the tank becomes overheated it stays that way. So, even if you let the bike sit, if it's a hot day, it won't make much difference. Also, riding down the road doesn't cool the tank much since the engine is constantly adding to the heat load.

For your situation, the only strategy I can suggest is on hot days to not fill the tank with more than 2-3 gallons. Then, when you get down to the red (4L) light, just add a single gallon or so. The gas at the station is stored underground and is cool. So, just drive a short distance, then add more cool fuel. That should keep the tank from becoming overheated.

One fix is to use a fuel line cooler (radiator), which I believe also circulates the fuel in the tank. This is more for more extreme environments (desert).

For the Northeast USA I've come up with my own solution that I'm testing this year for the first time. Basically, the strategy is to keep the heat from reaching the tank in the first place. So, I've added an insulation blanket on top of the engine block, insulation strips beneath the tank, and on the sides (inside) of the faring.

By keeping the heat away it stabilizes  tank temperature at some lower point. Also when going down the road it allows the tank to  cool down by convection with moving air. 

Why BMW didn't adequately insulate this bike is the big question. Be that as it may, so far the insulation seems to be working fine as I've not had one instance of overheating and I ride nearly every day. But, the real heat is yet to come this summer, so I'm not making any claims as of yet.  :suspect:

Google Johnny Blanket.  It is an easy work around for heat in general.  
You can also insulate the return line from the fuel rail to the tank which will limit additional heat transfer from the engine and radiator. 
Both fixes are pretty inexpensive and rather effective.

My solution is to fit a sidecar.  The motor is never leant over, It never smokes.

Al